The no-room-at-the-inn argument, used most recently in opposition to immigration from Mexico, has been with us throughout America's first two centuries. Yet, despite a 320 percent population increase, from 76 million in 1900 to nearly 320 million today, the U.S. has somehow managed to muddle through.

Now we're hearing the same lock-the-borders, build-a-beautiful-wall argument in response to refugees fleeing the civil war in Syria.

Europe has borne the brunt of the migration out of the Middle East -- and they've freaked out the most. European Union countries that ought to know better (Germany) and others choosing to ignore their treaty obligations (Hungary) have even restored the passport checkpoints whose elimination was the primary purpose of the EU.

European governments keep saying they're "overwhelmed" by migrants. As they do, the media has cut-and-pasted these official pronouncements into its "news" reports. But is it true?

Germany predicts that it will have taken in a million refugees by the end of this year. A "common European effort," its vice chancellor says, is required to cope with this "flood" of immigration. Bowing to international criticism, the U.S. promises to accept a not-so-whopping 10,000. It has become a campaign issue, with presidential candidate Bernie Sanders under pressure to name his own (higher) number.

For the sake of this argument, let's set aside moral responsibility. There probably wouldn't be a civil war in Syria, or an ISIS, or a resulting refugee crisis, had the U.S. and its European allies not armed and funded the Free Syrian Army in opposition to the Damascus government of President Bashar al-Assad.

Let's focus instead on the numbers. How many refugees can the U.S. and Europe allow to immigrate without facing an economic or political crisis?

When Vietnam defeated the U.S. in 1975, we took in 800,000 Vietnamese, Cambodians, Laotians and others who fled the victorious communists. That was just shy of a 0.4 percent population increase (from 216 million). It worked out well. Southeast Asian-Americans generated billions of dollars in increased economic activity while having one of the lowest rates of applying for public assistance of any ethnic group. Plus we got some great restaurants in the bargain.

Four million people, about a fifth of Syria's population, have fled the war. An estimated 42,500 refugees leave every day. It won't happen, but what if half of the remainder followed suit?

Eight million additional Syrians would increase the EU's population by 1.6 percent -- substantial and noticeable, but a drop in the bucket compared to German and Irish immigration to the U.S. from 1820 to 1870, which more than doubled the nation's population.

Were the U.S. to accept Syrians in the same proportion to its population as it took in Southeast Asians in the 1970s, we could absorb 1.2 million -- close to the total who have fled to Europe since the crisis began last year.

Though vast human migrations are psychologically traumatic and bureaucratically challenging for governments, there is a tendency to exaggerate the inability of people to cope. Leon Werth's riveting memoir "33 Days" describes the chaos of "l'Exode," when 8 million Frenchmen took to the roads to escape advancing Nazi forces during the summer of 1940. It has been described as the largest migration in history.

L'exode increased the population of the areas where it ended -- the southern French "Free Zone" administered by the collaborationist Vichy regime -- by 25 percent. Moreover, the host region was traumatized by war, military occupation and economic ruin. Still, people coped. For the most part, these internally displaced persons reported being treated with kindness until they were able to return home at the end of World War II. Of the many economic problems faced by Vichy, histories scarcely mention the burden of absorbing les Parisiens.

If wartime France could cope with one new arrival for every four inhabitants, we can deal with one in 250.

Nativists cite economic and demographic arguments against immigration to cover for their real motivation: racism and bigotry. If one or two million Syrians want to come here, the U.S. should welcome them with open arms.

Ted Rall, syndicated writer and the cartoonist for ANewDomain.net, is the author of the new book "Snowden," the biography of the NSA whistleblower. Want to support independent journalism? You can subscribe to Ted Rall at Beacon.

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